[Gazereths]

I know it's not strictly relevant, but my Mass Effect 3 Alliance edition front cover did that, it was originally held with hot glue so I just used some more to stick it back on and no one would ever be the wiser......I haven't opened it in a while though, maybe it's happened again. Carded figures though??? It would be noticeable.

I think unless you're gonna keep stuff in a perfectly controlled environment (humidity/heat etc) there's not much you can do to stop it.